Economic evaluations of the benefits of integrated weed management often only consider the benefits of management in the crop phase, and ignore the impact of rotational options. In particular, non-crop phases such as annual and perennial pasture phases can have a substantial impact upon weed population dynamics and economic returns. Moreover, extended perennial pasture phases are being promoted to address a range of onfarm sustainability issues such as excessive deep drainage (i.e. salinity), runoff and soil erosion. A stochastic bioeconomic model is developed to evaluate potential trade-offs and synergies between the goals of long-term weed management and achieving sustainability goals.